技术领域technical field
本发明属于基于相移点衍射干涉仪的光学元件面形检测方法领域，具体涉及一种波长调谐相移点衍射干涉测量方法。The invention belongs to the field of surface shape detection methods of optical elements based on a phase shift point diffraction interferometer, and in particular relates to a wavelength tuning phase shift point diffraction interferometry method.
背景技术Background technique
投影光刻物镜为了实现要求的分辨率及临界尺寸，需要光学系统波像差达到衍射极限.极紫外光刻的工作在波长为13～14nm的极紫外波段,这就要求光学系统的波像差要小于1nmRMS，而对单个反射镜镜面的面形偏差更是要到0.25nmRMS。要实现如此高精度的光学加工，首先要实现高精度的光学检测技术。常规干涉检测技术诸如菲索干涉仪、泰曼干涉仪受制于参考面精度的限制，难以达到如此高精度的光学系统波像差和光学元件面形检测。In order to achieve the required resolution and critical size of the projection lithography objective lens, the wave aberration of the optical system needs to reach the diffraction limit. The extreme ultraviolet lithography works in the extreme ultraviolet band with a wavelength of 13-14nm, which requires the wave aberration of the optical system It should be less than 1nmRMS, and the surface deviation of a single reflector should be 0.25nmRMS. To achieve such high-precision optical processing, high-precision optical detection technology must first be realized. Conventional interferometric detection technologies such as Fizeau interferometer and Tieman interferometer are limited by the accuracy of the reference surface, and it is difficult to achieve such high-precision detection of wave aberration of optical systems and surface shape of optical components.
点衍射干涉仪利用针孔衍射产生近似理想的球面波作为参考波，技术上消除了常规干涉仪中参考面带来的误差，提高了检测精度，可以用于极紫外投影光刻物镜中光学元件面形检测。检测光学元件面形时，由针孔衍射而出的近理想球面波分成两部分，一部分作为测试光经被检球面反射后，附带了被检球面的面形信息，在针孔板反射后通过中继光学系统打到光电探测器上；另一部分作为参考光经中继光学系统后直接打到光电探测器上。两路光干涉得到干涉图，对采集到的干涉图做处理后就能够得到被检球面的面形信息。在干涉测量技术中，精度最高的应属相移干涉术，将相移干涉术与点衍射干涉仪相结合的产物就是相移点衍射干涉仪。The point diffraction interferometer uses pinhole diffraction to generate an approximately ideal spherical wave as a reference wave, which technically eliminates the error caused by the reference surface in the conventional interferometer, improves the detection accuracy, and can be used for optical components in the extreme ultraviolet projection lithography objective lens Face detection. When testing the surface shape of an optical element, the near-ideal spherical wave diffracted by the pinhole is divided into two parts, one part is used as the test light and is reflected by the tested spherical surface, with the surface shape information of the tested spherical surface attached, and passes through The relay optical system hits the photodetector; the other part is directly hit the photodetector after passing through the relay optical system as the reference light. Two-way light interference is used to obtain an interferogram, and the surface shape information of the inspected spherical surface can be obtained after processing the collected interferogram. In the interferometry technology, the phase-shift interferometry with the highest precision is the product of the combination of phase-shift interferometry and point-diffraction interferometer is the phase-shift point-diffraction interferometer.
文章《Developmentofthepointdiffractioninterferometerforextremeultravioletlithography:Design,fabrication,andevaluation》J.Vac.Sci.Technol.B20,2449(2002)；描述了一种通过压电陶瓷相移器(PZT)移动被检镜实现相移干涉测量的点衍射干涉仪。这种相移方法有两个缺点，第一是当被检镜面形尺寸较大时，需要用载重大的相移器，而大载重相移器的制作技术难度大，成本高；同时在相移过程中会产生机械应力的变化，引入误差，从而影响测量结果。第二个是由于被检镜是球面或非球面光学元件，而相移方向是沿着被检镜光轴方向，导致被检镜边缘与中心在法线方向相移量不等。The article "Development of the point diffraction interferometer for extreme ultravioletlithography: Design, fabrication, and evaluation" J.Vac.Sci.Technol.B20, 2449 (2002); describes a point that realizes phase shift interferometry by moving the inspected mirror through a piezoelectric ceramic phase shifter (PZT). Diffraction interferometer. This phase shifting method has two disadvantages. The first is that when the size of the mirror to be inspected is large, a phase shifter with a heavy load is required, and the manufacturing technology of a phase shifter with a large load is difficult and expensive; Changes in mechanical stress will occur during the shifting process, which will introduce errors and affect the measurement results. The second is because the inspected mirror is a spherical or aspheric optical element, and the phase shift direction is along the optical axis of the inspected mirror, resulting in different phase shifts in the normal direction between the edge and the center of the inspected mirror.
文章《Visiblelightpoint-diffractioninterferometerfortestingofEUVLoptics》Proc.ofSPIEVol.6151,61510E,(2006)描述了一采用短相干激光器中利用压电陶瓷移动角锥反射镜实现相移测量的点衍射干涉仪，这种方法能够解决移动被检镜进行相移的缺点。但是在这种形式的干涉仪中，必须将参考光和测试光分开，形成双臂结构，这样就会导致参考光和测试光之间的非共光路，增大对环境的敏感度。The article "Visible light point-diffraction interferometer for testing of EUVLoptics" Proc.ofSPIE Vol.6151, 61510E, (2006) describes a point diffraction interferometer that uses a piezoelectric ceramic moving corner mirror in a short coherent laser to achieve phase shift measurement. This method can solve the problem of moving Disadvantages of phase shifting of the inspected mirror. But in this form of interferometer, the reference light and the test light must be separated to form a double-arm structure, which will lead to a non-common optical path between the reference light and the test light, increasing the sensitivity to the environment.
发明内容Contents of the invention
为了解决现有利用压电陶瓷相移器(PZT)实现相移干涉测量的点衍射干涉仪对球面或非球面的被检镜测量时，其沿着被检镜光轴方向的相移的方式会导致被检镜边缘与其中心在法线方向相移量不等，以及当被检光学元件面形尺寸较大时，所用大载重相移器制作难度大，并会在相移时因自重应力而使测量结果引入误差。而采用短相干激光器中利用压电陶瓷移动角锥反射镜实现相移测量的点衍射干涉仪则必须将参考光和测试光分开并形成双臂结构，从而导致参考光和测试光之间的非共光路，增大对环境的敏感度的技术问题，本发明提供一种波长调谐相移点衍射干涉测量方法。In order to solve the existing method of phase shifting along the optical axis of the inspected mirror when the existing point diffraction interferometer using piezoelectric ceramic phase shifter (PZT) to realize the phase shift interferometry measures the spherical or aspheric inspected mirror It will cause the phase shift between the edge of the inspected mirror and its center to be different in the normal direction, and when the surface size of the inspected optical element is large, it is difficult to manufacture the heavy-duty phase shifter, and it will be affected by the self-weight stress during the phase shift. This leads to errors in the measurement results. However, the point diffraction interferometer that uses piezoelectric ceramic moving corner mirrors in short-coherent lasers to achieve phase shift measurement must separate the reference beam from the test beam and form a double-armed structure, resulting in an inconsistency between the reference beam and the test beam. Common optical path, increase the technical problem of the sensitivity to the environment, the present invention provides a wavelength tuning phase shift point diffraction interferometry method.
本发明解决技术问题所采取的技术方案如下：The technical solution adopted by the present invention to solve the technical problems is as follows:
一种波长调谐相移点衍射干涉测量方法包括如下步骤：A wavelength-tuned phase-shift point diffraction interferometry method comprises the following steps:
步骤1：对波长调谐相移点衍射干涉测量装置初始化，其具体包括如下子步骤：Step 1: Initialize the wavelength-tuned phase-shift point diffraction interferometry device, which specifically includes the following sub-steps:
步骤1.1：设定波长调谐相移点衍射干涉测量时的移相步数N、移相角度和干涉腔的长度h，所述干涉腔的长度h为被检光学元件曲率半径R的两倍；Step 1.1: Set the number of phase shift steps N and phase shift angle during wavelength tuning phase shift point diffraction interferometry And the length h of the interference cavity, the length h of the interference cavity is twice the curvature radius R of the optical element to be tested;
步骤1.2：启动波长调谐相移点衍射干涉测量装置，由主控计算机读取并记录波长计测得的当前激光波长检测信号λ1、功率计测得的当前激光功率检测信号P1以及CCD相机采集的第一幅干涉图像I1；Step 1.2: Start the wavelength-tuned phase-shift point diffraction interferometry device, read and record the current laser wavelength detection signal λ1 measured by the wavelength meter, the current laser power detection signal P1 measured by the power meter and the CCD camera by the main control computer The first interferometric image I1 collected;
步骤1.3：波长求解公式：Step 1.3: Wavelength solution formula:
式(1)中，i＝2,3…N；In formula (1), i=2,3...N;
依据式(1)，由主控计算机根据步骤1.1设定的移相步数N、移相角度和干涉腔的长度h依次计算移相到第j(j＝1,2,3…N)步时需要的各个激光波长数值组λi；According to the formula (1), the number of phase-shifting steps N and the phase-shifting angle set by the main control computer according to step 1.1 and the length h of the interference cavity to calculate the phase shifting to the jth (j=1,2,3...N) step in turn for each laser wavelength value group λi needed;
步骤2：采用逐步调谐激光实现波长移相的方法完成相移点衍射干涉图集的采集，其具体包括如下子步骤：Step 2: Complete the acquisition of the phase-shifted point diffraction interferogram set by gradually tuning the laser to achieve wavelength phase shifting, which specifically includes the following sub-steps:
步骤2.1：主控计算机通过可调谐激光器控制模块向可调谐激光器发出激光波长调谐命令，使可调谐激光器发出激光波长调谐至λi(i＝2,3…N)，所述λi依次经由步骤1.3所获得的激光波长数值组确定；当可调谐激光器每完成一次波长调谐后，其均通过可调谐激光器控制模块向主控计算机发送波长调谐完成反馈信号；主控计算机每次收到所述波长调谐完成反馈信号后，都通过CCD相机采集控制模块向CCD相机发出图像信号采集命令；CCD相机按照图像信号采集命令依次采集第j(j＝1,2,3…N)幅干涉图像Ii(i＝2,3…N)并将其每次所采集到的干涉图像信号通过CCD相机采集控制模块发送给主控计算机；主控计算机读取并记录波长计每次测得的当前激光波长检测信号λi、,(功i率计1,每2次测得的当前激光波长检测信号Pi(i＝2,3…N)以及CCD相机每次采集的第j幅干涉图像Ii(i＝2,3…N)，即：获得了相移点衍射干涉图集；Step 2.1: The main control computer sends a laser wavelength tuning command to the tunable laser through the tunable laser control module, so that the tunable laser emits a laser wavelength tuned to λi (i=2,3...N), and the λi goes through the steps in turn 1.3 The obtained laser wavelength value group is determined; when the tunable laser completes a wavelength tuning, it sends a wavelength tuning completion feedback signal to the main control computer through the tunable laser control module; the main control computer receives the wavelength every time After the feedback signal is tuned, the image signal acquisition command is sent to the CCD camera through the CCD camera acquisition control module; the CCD camera sequentially acquires the jth (j=1, 2, 3...N) interference image Ii ( i=2,3...N) and the interference image signal collected each time is sent to the main control computer through the CCD camera acquisition control module; the main control computer reads and records the current laser wavelength detection measured by the wavelength meter each time Signal λi ,, (power i power meter 1, the current laser wavelength detection signal Pi (i=2,3...N) measured every 2 times and the jth interference image Ii (i =2,3...N), that is: obtained the phase-shift point diffraction interferogram set;
步骤2.2：主控计算机令j＝i+1并重复步骤2.1的测量过程，直至j＝i+1达到步骤1.1设定的移相步数N时，检测结束；Step 2.2: the main control computer orders j=i+1 and repeats the measurement process of step 2.1 until j=i+1 reaches the phase shifting steps N set in step 1.1, and the detection ends;
步骤3：对相移点衍射干涉图集进行亮度修正：Step 3: Apply brightness correction to the phase-shifted point-diffraction interferogram set:
由主控计算机调取步骤2.1存储的功率计测得的当前激光波长检测信号Pi,(i＝1,2,3...N)集合及对应的相移点衍射干涉图集Ii,(i＝1,2,3...N)，代入下式：The main control computer retrieves the current laser wavelength detection signal Pi , (i=1,2,3...N) set and the corresponding phase shift point diffraction interferogram set Ii measured by the power meter stored in step 2.1, (i=1,2,3...N), substitute into the following formula:
所述Ii',(i＝1,2,3...N)即为亮度修正后的相移点衍射干涉图集；The Ii ', (i=1,2,3...N) is the brightness-corrected phase-shift point diffraction interferogram set;
步骤4：对步骤3所述修正后的相移点衍射干涉图集中的N幅干涉图进行移相位算法处理，则可获包含被检光学元件面形信息的数据，进而完成波长调谐相移点衍射干涉测量的全过程。Step 4: Perform phase-shift algorithm processing on the N interferograms in the corrected phase-shift point diffraction interferogram set described in step 3, then the data containing the surface information of the inspected optical element can be obtained, and then the wavelength tuning phase-shift point is completed. The whole process of diffraction interferometry.
本发明的有益效果是：该相移点衍射干涉测量装置利用波长调谐的激光器实现移相，进而完成相移点衍射干涉测量，无需采用压电陶瓷相移器(PZT)或利用压电陶瓷移动角锥反射镜等机械移动部件进行移相，因此很好地克服了机械移相装置制作难度大、成本高的问题，并是测量结果避免了因机械移相器自重引入应力形变误差。The beneficial effects of the present invention are: the phase-shift point diffraction interferometry device uses a wavelength-tuned laser to achieve phase shifting, and then completes the phase-shift point diffraction interferometry without using a piezoelectric ceramic phase shifter (PZT) or using piezoelectric ceramics to move Mechanical moving parts such as corner mirrors are phase-shifted, so the problems of difficulty and high cost in the manufacture of mechanical phase-shifting devices are well overcome, and the measurement results avoid stress-deformation errors caused by the weight of the mechanical phase-shifter.
附图说明Description of drawings
图1是本发明一种波长调谐相移点衍射干涉测量装置的系统原理图。Fig. 1 is a system schematic diagram of a wavelength-tuned phase-shift point diffraction interferometry device according to the present invention.
具体实施方式detailed description
下面结合附图对本发明做进一步详细说明。The present invention will be described in further detail below in conjunction with the accompanying drawings.
如图1所示，本发明一种波长调谐相移点衍射干涉测量装置包括可调谐激光光源模块100、点衍射干涉模块200和控制系统300。可调谐激光光源模块100包括：可调谐激光器101，用于将可调谐激光器101出射的激光分束至波长计104的第一分光镜102，用于探测可调谐激光器101出射激光中心波长的波长计104，用于探测激光器出射激光能量的功率计105和用于将可调谐激光器101出射的激光分束至功率计105的第二分光镜103。点衍射干涉模块200包括针孔板202、用于将激光束聚焦到针孔板亚微米针孔上的光束调整镜组201、用于对由被检光学元件反射回来的检测光进行成像的干涉仪成像镜组204和CCD相机205。控制系统300包括可调谐激光器控制模块301、CCD相机采集控制模块302和主控计算机303。As shown in FIG. 1 , a wavelength-tuned phase-shift point-diffraction interferometry device of the present invention includes a tunable laser light source module 100 , a point-diffraction interference module 200 and a control system 300 . The tunable laser light source module 100 includes: a tunable laser 101, which is used to split the laser beam emitted by the tunable laser 101 to a first spectroscope 102 of a wavelength meter 104, and a wavelength meter for detecting the central wavelength of the laser emitted by the tunable laser 101 104 , a power meter 105 for detecting laser energy emitted by the laser and a second beam splitter 103 for splitting the laser light emitted by the tunable laser 101 to the power meter 105 . The point diffraction interference module 200 includes a pinhole plate 202, a beam adjusting mirror group 201 for focusing the laser beam on the submicron pinhole of the pinhole plate, and an interference lens for imaging the detection light reflected by the optical element under inspection. Instrument imaging lens group 204 and CCD camera 205. The control system 300 includes a tunable laser control module 301 , a CCD camera acquisition control module 302 and a main control computer 303 .
可调谐激光器101、第一分光镜102、第二分光镜103、光束调整镜组201及针孔板202位于同一光轴线上依次排列。凹面镜被检光学元件203放置时使其光轴与针孔板202的法线成一定夹角且凹面镜面形的球心与小孔重合。干涉仪成像镜组204放置时使其光轴与被检光学元件203的光轴关于针孔板202的法线对称。CCD相机205位于被检光学元件203经干涉仪成像镜组204所成像的像面上。波长计104与可调谐激光器控制模块301相连，其光轴位于第一分光镜102的反射光的光路上。功率计105与主控计算机303连接，其光轴放置与第二分光镜103的反射光的光路上。可调谐激光器控制模块301分别与可调谐激光器101、波长计104及主控计算机303相连接。CCD相机采集控制模块302分别与CCD相机205和主控计算机303相连。主控计算机303分别通过总线与可调谐激光器控制模块301、CCD相机采集控制模块302及功率计105相连接。The tunable laser 101 , the first beam splitter 102 , the second beam splitter 103 , the light beam adjustment mirror group 201 and the pinhole plate 202 are arranged on the same optical axis in sequence. When the concave mirror optical element 203 to be inspected is placed, its optical axis forms a certain angle with the normal line of the pinhole plate 202 and the spherical center of the concave mirror coincides with the small hole. The interferometer imaging mirror group 204 is placed so that its optical axis is symmetrical to the optical axis of the optical element 203 to be inspected with respect to the normal of the pinhole plate 202 . The CCD camera 205 is located on the image plane formed by the inspected optical element 203 through the interferometer imaging lens group 204 . The wavelength meter 104 is connected to the tunable laser control module 301 , and its optical axis is located on the optical path of the reflected light of the first beam splitter 102 . The power meter 105 is connected with the main control computer 303 , and its optical axis is placed on the optical path of the reflected light of the second beam splitter 103 . The tunable laser control module 301 is respectively connected with the tunable laser 101 , the wavelength meter 104 and the main control computer 303 . The CCD camera acquisition control module 302 is connected with the CCD camera 205 and the main control computer 303 respectively. The main control computer 303 is respectively connected with the tunable laser control module 301 , the CCD camera acquisition control module 302 and the power meter 105 through the bus.
可调谐激光器101出射的激光的一部分经过第一分光镜102反射至波长计104用于激光中心波长的测量，可调谐激光器101出射的激光的另一部分直接透射至第二分光镜103。第二分光镜103的入射激光一部分经过第二分光镜103反射至功率计105用于激光功率的监测，第二分光镜103的入射激光的另一部分透射至光束调整镜组201。透射至光束调整镜组201的光束经过整形聚焦后照射到位于针孔板202的针孔上并发生衍射。由针孔板202产生的衍射光，其一部分作为参考光直接经过干涉仪成像镜组204透射至CCD相机205，衍射光的另一部分作为测试光照射到被检光学元件203上，再依次经被检光学元件203反射、针孔板202反射和干涉仪成像镜组204透射至CCD相机205，并与前述参考光干涉。可调谐激光器101、可调谐激光器控制模块301和波长计104共同构成一个能进行精确波长调节的闭环反馈调节系统。可调谐激光器控制模块301与主控计算机303通过总线进行通讯，可调谐激光器控制模块301接收并执行主控计算机303发出的波长调谐命令并将调谐完成信号反馈给主控计算机303。主控计算机303能够采集功率计105探测到得功率信息并记录。CCD相机采集控制模块302与主控计算机303通过总线通讯，CCD相机采集控制模块302接收并执行主控计算机303发出的图像采集命令并将采集到得图像传输回主控计算机303。Part of the laser light emitted by the tunable laser 101 is reflected by the first beam splitter 102 to the wavelength meter 104 for measuring the central wavelength of the laser, and the other part of the laser light emitted by the tunable laser 101 is directly transmitted to the second beam splitter 103 . Part of the incident laser light from the second beam splitter 103 is reflected by the second beam splitter 103 to the power meter 105 for monitoring the laser power, and another part of the incident laser light from the second beam splitter 103 is transmitted to the beam adjusting mirror group 201 . The beam transmitted to the beam adjustment lens group 201 is shaped and focused, and then irradiates the pinhole on the pinhole plate 202 and undergoes diffraction. Part of the diffracted light generated by the pinhole plate 202 is directly transmitted to the CCD camera 205 through the interferometer imaging mirror group 204 as reference light, and the other part of the diffracted light is irradiated on the optical element 203 to be inspected as test light, and then passed through the Reflected by the optical detection element 203 , reflected by the pinhole plate 202 and transmitted by the interferometer imaging mirror group 204 to the CCD camera 205 , and interferes with the aforementioned reference light. The tunable laser 101 , the tunable laser control module 301 and the wavelength meter 104 together form a closed-loop feedback adjustment system capable of precise wavelength adjustment. The tunable laser control module 301 communicates with the main control computer 303 through the bus. The tunable laser control module 301 receives and executes the wavelength tuning command sent by the main control computer 303 and feeds back the tuning completion signal to the main control computer 303 . The main control computer 303 can collect and record the power information detected by the power meter 105 . The CCD camera acquisition control module 302 communicates with the main control computer 303 through the bus. The CCD camera acquisition control module 302 receives and executes the image acquisition command sent by the main control computer 303 and transmits the captured image back to the main control computer 303 .
本发明的波长调谐相移点衍射干涉测量方法包括如下步骤：The wavelength tuning phase shift point diffraction interferometry method of the present invention comprises the following steps:
步骤1：对波长调谐相移点衍射干涉测量装置初始化，其具体包括如下子步骤：Step 1: Initialize the wavelength-tuned phase-shift point diffraction interferometry device, which specifically includes the following sub-steps:
步骤1.1：设定波长调谐相移点衍射干涉测量时的移相步数N、移相角度和干涉腔的长度h，干涉腔的长度h为被检光学元件203曲率半径R的两倍。Step 1.1: Set the number of phase shift steps N and phase shift angle during wavelength tuning phase shift point diffraction interferometry and the length h of the interference cavity, the length h of the interference cavity is twice the curvature radius R of the optical element 203 to be tested.
步骤1.2：启动本发明所述波长调谐相移点衍射干涉测量装置，由主控计算机303读取并记录波长计104测得的当前激光波长检测信号λ1、功率计105测得的当前激光功率检测信号P1以及CCD相机205采集的第一幅干涉图像I1。Step 1.2: Start the wavelength-tuned phase-shift point diffraction interferometry device of the present invention, read and record the current laser wavelength detection signal λ1 measured by the wavelength meter 104 and the current laser power measured by the power meter 105 by the main control computer 303 The detection signal P1 and the first interference image I1 collected by the CCD camera 205 .
步骤1.3：波长求解公式：Step 1.3: Wavelength solution formula:
式(1)中，i＝2,3…N。In formula (1), i=2, 3...N.
依据式(1)，由主控计算机303根据步骤1.1设定的移相步数N、移相角度和干涉腔的长度h依次计算移相到第j(j＝1,2,3…N)步时需要的各个激光波长数值组λi,(i＝1,2…N)。According to formula (1), by main control computer 303 according to step 1.1 phase-shift step number N, phase-shift angle of setting and the length h of the interference cavity to sequentially calculate the value groups λi , (i=1, 2...N) of each laser wavelength required for phase shifting to the jth step (j=1, 2, 3...N).
步骤2：采用逐步调谐激光实现波长移相的方法完成相移点衍射干涉图集的采集，其具体包括如下子步骤：Step 2: Complete the acquisition of the phase-shifted point diffraction interferogram set by gradually tuning the laser to achieve wavelength phase shifting, which specifically includes the following sub-steps:
步骤2.1：主控计算机303通过可调谐激光器控制模块301向可调谐激光器101发出激光波长调谐命令，使可调谐激光器101发出激光波长调谐至λi，i值依次取i＝2,3…N。λi依次经由步骤1.3所获得的激光波长数值组确定。当可调谐激光器101每完成一次波长调谐后，其均通过可调谐激光器控制模块301向主控计算机303发送波长调谐完成反馈信号。主控计算机303每次收到波长调谐完成反馈信号后，都通过CCD相机采集控制模块302向CCD相机205发出图像信号采集命令。CCD相机205按照图像信号采集命令依次采集第j(j＝1,2,3…N)幅干涉图像Ii并将其每次所采集到的干涉图像信号通过CCD相机采集控制模块302发送给主控计算机303。主控计算机303读取并记录波长计104每次测得的当前激光波长检测信号λi、,(功i率计1,1025每次N测得)的当前激光波长检测信号Pi以及CCD相机205每次采集的第j幅干涉图像Ii，即：获得了相移点衍射干涉图集。Step 2.1: The main control computer 303 sends a laser wavelength tuning command to the tunable laser 101 through the tunable laser control module 301, so that the tunable laser 101 can tune the laser wavelength to λi, and the value ofi takes i=2, 3...N in turn. λi is sequentially determined through the laser wavelength value group obtained in step 1.3. When the tunable laser 101 completes wavelength tuning each time, it sends a wavelength tuning completion feedback signal to the main control computer 303 through the tunable laser control module 301 . The main control computer 303 sends an image signal acquisition command to the CCD camera 205 through the CCD camera acquisition control module 302 each time after receiving the feedback signal of completion of wavelength tuning. The CCD camera 205 collects the jth (j=1, 2, 3...N) interference image Ii sequentially according to the image signal acquisition order and sends the interference image signal collected each time to the main body through the CCD camera acquisition control module 302 control computer 303. The main control computer 303 reads and records the current laser wavelength detection signal λi measured by the wavelength meter 104 each time, the current laser wavelength detection signalPi and the CCD camera 205 The j-th interference image Ii collected each time, that is, a set of phase-shifted point diffraction interference atlases is obtained.
步骤2.2：主控计算机303令j＝i+1并重复步骤2.1的测量过程，直至j＝i+1达到步骤1.1设定的移相步数N时，检测结束。Step 2.2: The main control computer 303 sets j=i+1 and repeats the measurement process of step 2.1 until j=i+1 reaches the number N of phase shifting steps set in step 1.1, and the detection ends.
步骤3：对相移点衍射干涉图集进行亮度修正：Step 3: Apply brightness correction to the phase-shifted point-diffraction interferogram set:
由于移相算法要求在移相过程中保持光强的恒定，而波长调谐激光器在波长调谐时很难保证这一点，因此，需要对干涉图进行亮度修正。本发明在采集每幅相移点衍射干涉图像同时采集激光功率值，然后根据功率变化对相移点衍射干涉图集进行亮度修正，其具体方法如下：Since the phase-shifting algorithm requires that the light intensity be kept constant during the phase-shifting process, it is difficult for the wavelength-tuned laser to ensure this when the wavelength is tuned. Therefore, the brightness correction of the interferogram is required. The present invention collects the laser power value at the same time when collecting each phase-shift point diffraction interference image, and then corrects the brightness of the phase-shift point diffraction interference atlas according to the power change. The specific method is as follows:
由主控计算机303调取步骤2.1存储的功率计105测得的当前激光波长检测信号Pi,(i＝1,2,3...N)集合及对应的相移点衍射干涉图集Ii,(i＝1,2,3...N)，代入下式：The main control computer 303 retrieves the current laser wavelength detection signal Pi , (i=1, 2, 3...N) set and the corresponding phase shift point diffraction interferogram set I measured by the power meter 105 stored in step 2.1i ,(i=1,2,3...N), substitute into the following formula:
Ii',(i＝1,2,3...N)即为亮度修正后的相移点衍射干涉图集。Ii ', (i=1,2,3...N) is the phase-shift point diffraction interferogram set after brightness correction.
步骤4：对步骤3所述修正后的相移点衍射干涉图集中的N幅干涉图进行移相位算法处理，则可获包含被检光学元件203面形信息的数据，进而完成波长调谐相移点衍射干涉测量的全过程。所述移相位算法是对干涉图进行处理的经典方法，例如当N＝5时，采用的5步移相算法一般是：由5幅干涉图得到一个结果。当N＝7时，可采用7步移相算法，由7幅干涉图得到一个结果。Step 4: Perform phase-shift algorithm processing on the N interferograms in the corrected phase-shifted point diffraction interferogram set described in step 3, and then obtain data containing the surface information of the inspected optical element 203, and then complete the wavelength tuning phase shift The whole process of point diffraction interferometry. The phase-shifting algorithm is a classical method for processing interferograms. For example, when N=5, the 5-step phase-shifting algorithm adopted is generally: A result is obtained from 5 interferograms. When N=7, a 7-step phase-shifting algorithm can be used, A result is obtained from 7 interferograms.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104655053B (en)* | 2013-11-25 | 2017-06-27 | 南京理工大学 | Measurement Method of Curvature Radius of Spherical Mirror Based on Pinhole Point Diffraction Interferometer |
| CN103727901A (en)* | 2014-01-14 | 2014-04-16 | 中国科学院长春光学精密机械与物理研究所 | Wavelength phase-shifting method based inter-planar parallelism detection method |
| CN105277338B (en) | 2014-07-04 | 2018-10-26 | 中国科学院长春光学精密机械与物理研究所 | Large-numerical aperture phase shift double needle hole diffraction interferometer and its test method |
| CN106289096B (en)* | 2015-12-29 | 2019-08-23 | 中国科学院长春光学精密机械与物理研究所 | A kind of convex spherical mirror surface testing system and detection method |
| CN106949846B (en)* | 2017-02-16 | 2018-12-07 | 上海大学 | Handle ultra-thin parallel flat staggered form interference fringe method in wavelength phase shift interference |
| CN107702645B (en)* | 2017-10-10 | 2020-03-17 | 西安交通大学 | Multi-wavelength interference phase detection method for point diffraction measurement system |
| CN111366099B (en)* | 2020-03-26 | 2021-11-05 | 上海大学 | Pre-analysis-based interference weighted sampling dephasing analysis method and measurement system under any cavity length |
| CN112462386A (en)* | 2020-10-26 | 2021-03-09 | 天津大学 | Modular continuous frequency modulation laser radar's two-dimensional topography scanning device |
| CN113639664B (en)* | 2021-08-12 | 2022-03-29 | 江苏科技大学 | Method for measuring curvature radius of optical lens and detecting lens defect step by step |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6020965A (en)* | 1997-03-11 | 2000-02-01 | Olympus Optical Co., Ltd. | Phase interference microscope |
| CN102288105A (en)* | 2011-07-22 | 2011-12-21 | 大连民族学院 | Structure and detection method of optical fiber point-diffraction interferometer |
| CN102798341A (en)* | 2012-07-23 | 2012-11-28 | 中国科学院长春光学精密机械与物理研究所 | Method used for improving measuring accuracy of point-diffraction interferometer |
| CN102829733A (en)* | 2012-08-03 | 2012-12-19 | 中国计量学院 | Fringe contrast ratio-adjustable large-numerical value bore diameter point-diffraction interference device and method |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4208565B2 (en)* | 2002-12-20 | 2009-01-14 | キヤノン株式会社 | Interferometer and measurement method having the same |
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6020965A (en)* | 1997-03-11 | 2000-02-01 | Olympus Optical Co., Ltd. | Phase interference microscope |
| CN102288105A (en)* | 2011-07-22 | 2011-12-21 | 大连民族学院 | Structure and detection method of optical fiber point-diffraction interferometer |
| CN102798341A (en)* | 2012-07-23 | 2012-11-28 | 中国科学院长春光学精密机械与物理研究所 | Method used for improving measuring accuracy of point-diffraction interferometer |
| CN102829733A (en)* | 2012-08-03 | 2012-12-19 | 中国计量学院 | Fringe contrast ratio-adjustable large-numerical value bore diameter point-diffraction interference device and method |
| Title |
|---|
| 《基于光学设计软件的相移点衍射干涉仪建模》;张海涛;《中国光学与应用光学》;20101231;第3卷(第6期);第616-622页* |
| 《点衍射干涉仪基准波前测试技术研究》;邵晶等;《中国激光》;20110531;第３８卷(第５期);第0508003-1至０５０８００３－６页* |
| Publication number | Publication date |
|---|---|
| CN103398655A (en) | 2013-11-20 |
| Publication | Publication Date | Title |
|---|---|---|
| CN103398655B (en) | A kind of wavelength tuning phase shift point diffraction interference measuring method | |
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